SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '814d5df813ae742bd05655d50612660f999976acef43ec2090a862b297ca66d0' 
  AND token = 'MvCSr0xgTmYWzwWMMhPCkuGKiRQdeyHksOc4/BoRIns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}